1. Field of the Invention
The present invention relates to an information searching device for automatically searching desired image information from a record web having image information and a searching mark.
2. Description of the Prior Art
In order to search a desired frame from a roll of microfilm with a searching mark (hereinafter referred to as "blip") placed thereon, devices such as film reader or reader printer utilizing the blip and incorporating a search function therein have heretofore been used. Using this type of search system, the desired image frame is searched in such a manner that a microfilm with image film and blip corresponding to the image frame placed thereon is fed between a stationary light source and a photoelectric converter element, rays of light passed through the blip being detected by means of said photoelectric converter element, and electrical signals from the photoelectric converter element obtained by discontinuously exposing the photoelectric converter element with the light thus transmitted when the film is moved are counted by means of a counter, and then the value counted by the counter is compared with a frame number placed on the desired image.
Lately, an image transmission system has been utilized, wherein the image on the microfilm is scanned at a light spot to convert it into an electric signal corresponding to gradation of the image, and this electrical signal is transmitted to an indicating means located at a terminal through a transmission path to effect electric-to-optical conversion thereby reproducing the image for the reading or printing. However, since this image transmission system is to image and scan the image plane, the scanning mechanism thereof prevents the above-described searching system from being utilized. According to prior art searching systems, for the purpose of properly stopping the film in position after the blip corresponding to the desired frame has been counted, the position of stopping the film has been determined by the relative positional relationship between a slit made in an exposure light path from the stationary light source and the blip on the film, or by the relative positional relationship between a projected image of the blip projected through an optical system and the photoelectric converter element. In either case, therefore, the film position is mechanically determined. In the event that various forms of a film are used wherein the relative record position between the image frame and the blip is different, the film stop position will be changed. From this reason, the position of an image frame projected on a screen of a reader when the film is stopped changes with the form of film to cause the desired image to be displaced partially or completely from the screen, and as a result the desired image cannot be read properly from the screen at the same time when searching has been completed. In order to place the image in properly readable condition, an operator must adjust or move the film to correct the stop position thereof. The prior art system further possesses a disadvantage such that even if the same form of film is used, the stop position of film could not be changed as desired.